CCTV footage released by the Sri Lankan government, according to Reuters, shows a man with a rucksack entering St Sebastian's Church in Negombo on Easter Sunday moments before a deadly blast.

The footage has been getting a lot of attention as various media organisations are linking the man to involvement in the attack, however Euronews currently has had no confirmation of that from Sri Lankan police. There is also no official verification of the man's identity.

On Tuesday afternoon however, Prime Minister Ranil Wickremesinghe told a press conference that the person depicted in the CCTV video was a suspect. "I can confirm this man is a suspect," he said.

The video, obtained by the private Sri Lankan channel Siyatha News, was captured before one of the explosions, which killed more than 50 people and almost entirely blew off the roof of the church.

St Sebastian's was one of eight sites where bombings took place, killing over 300 people and injuring around 500.

READ MORE: Sri Lanka explosions: What we know so far

The attacks marked the most significant violence in the country since a bloody civil war ended 10 years ago.

On Monday, ministers held a press conference and said local Islamist movement, the National Thowheed Jamath (NTJ), was behind the attacks.

No group has claimed responsibility for the blasts.

Police said they have arrested 40 people since Sunday and that the suspects were mainly Sri Lankans.